Having repeating problems with hotkeys and mouse controls, how can I fix them?
ESC Required

One possibility would be that you've accidentally activated a selection or an operator awaiting further input? 

In this case the Header of your 3D View might change to something like:


Example for Knife Tool

ESC would cancel such operations. 

Possible Solution

On Windows you can have different keyboard layouts and switch between them by pressing Left Alt-Shift which happens very easy when using Blender.
If this is the reason change the Hotkeys in Windows: Control panel / Region &amp; Languages / Keyboard &amp; languages / Change keyboard / Advanced key setting

Numeric Input

On my machine the numeric block is independent from whether or not the NumLock is active it never switches the layers as the normal digits would do. The option Emulate Numpad in the User Preferences / Input would make the main keys 1 to 0 to switch the Views Orientation. But it's never the other way around.